As described in Patent Document 1, an apparatus is conventionally known that shapes a gear by causing a hob to rotate at a high speed and then by gear cutting a workpiece with cutting teeth of the hob.
Furthermore, as a gear machining apparatus that shapes a gear by grinding a workpiece with a grinding wheel, an apparatus is known that shapes a gear by dressing a threaded grinding wheel with a dresser having a shape corresponding to a shape of the gear to be machined and then by causing the threaded grinding wheel to grind the workpiece into a shape corresponding to the shape of the dresser.